Snap switch



April 17, 1962 H. c. KRYDER 3,030,466

SNAP SWITCH Filed Oct. 13, 1958 6 I? I/ I8 HAROLD c. KRYDER I a o-. o1

E@ E Qa ATTORNEY corporation or Delaware Filed Oct. 13, 1958, Ser. No. 766,759 3 Claims. (Cl. 20D- 67) The present invention is directed to an improved precision snap action switch, and more particularly to a switch of this type which is oapable of being miniaturized to a very high degree Without detrimental etfects being realized insofar as contact pressure, contact wiping, and dead break, electric load conveying and operating characteristics, and ease of assembly are concerned.

The snap switch disclosed herein includes a snap mechanism essentially comprised of tlrre-e interconnected elements: a first tension member having a rst extremity pivotally associated with the switch be; a second tension member having a first extremity pivotally associated with the second extremity of the rst lever and having contact means disposed at the second extremity for coperation with a pair of xed terminal members; and a compression spring having a rst extremity pivotally associated with the switch base and having a second extremity operatively associated with a portion of the second lever near the contact means thereof.

The snap mechanism and the pivotal connections are so arranged that adequate contact wiping is provided and the tendency of dead break is minimized. Further, the compression spring serves to act both as a snap action means and a return means upon actuation and deactuation of the mechanism, respectively. The compression spring also serves to provide positive contact force between the contact means and the terminal members iny either condition of the mechanism.

As indicated above, the teaching disclosed herein is particularly adapted to be highly miniaturized. In fact, switches have been constructed in accordance with the present disclosure which occupy approximately 1/25 cubic inch and weigh approximately 3%8 ounce, and which are operable by 6 ounces of force and capable of switching amperes at 250 v. A.C. or 30 v. D.C.

Therefore, it is an object of this invention to provide a novel three element snap switch mechanism.

Another object of the present invention is to provide a snap switch mechanism as set forth above which can be highly miniaturized without detrimental eiects being realized insofar as general switch characteristics and ease of assembly of the snap switch mechanism are concerned.

These and other objects will become more apparent from a reading of the following specification and appended claims -in which:

FIGURE l is a sectional view of a switch including the novel snap switch mechanism shown in the deactuated condition;

FIGURE 2 is a top plan view of the structure of FIG- URE l taken with the cover removed; and

FIGURE 3 is a partial sectional view of the switch shown in the actuated condition.

In FIGURES l, 2, and 3, a switch case 10, comprising `a molded switch base 11 and a molded switch cover 12 both formed of insulating material, is shown. The base 11 and the cover 12 are secured together by an appropriate adhesive applied at the joint therebetween. A pair of mounting holes 14 are provided in the base 1'1. Terminals 16, 17 and 18 are molded in the base 11 and include lower portions 16a, 17a, and 18a for the connection thereto of appropriate conductors, not shown. Near the upper extremity of upper portion 16h of the terminal 16, a notch 20 -is provided. A first conducting rigid tension member 22 includes an opening 23, the leftward tent s spaans Patented Apr. 17,1962

ice

extremity 23a of which cooperates with the notch 20 to the right end portion of lever 2S, a contact 27 is provided.

'Io the upper por-tion 16b of terminal member 16, at the upper extremity of the base 11, an angle member 30 is secured thereto. A notch 32 is provided nea-r the extremity of upstanding leg 30a of the angle member 30. A preformed conducting C spring member 35 includes a rst extremity 35a associated with the notch 32 of the upstanding leg 30a of the angle support 30 to form a pivotal connection D and further includes a second T shaped extremity 35h associated with the rightward ex` tremity 26b of the opening 26 of the lever 25 to form a pivotal connection E. As is of course obvious, the opening 26 in the lever 25 accommodates the C spring 35 and also the upistanding leg 30a of the angle support 30.`

Terminal members 17 and 1S include upper portions'v 17b and lb which serve as upper and lower stops for' the contact 27 upon deactuation and actuation of the snap switch 10, respectively.

The cover 12 includes an opening 39 in which a molded plunger 40, formed of insulating material, is slidably dis-v posed. The lower extremity of the plunger 40 acts on the lever 22 so that upon downward movement of the plunger 40, actuation of the snap switch 10 takes place and upon subsequent upward movement, deactuationv takes place.

The arrangement of the levers 22 and 25, the C spring 35 and the pivotal connections A, B, D, and E allows for the C spring to act both as a snap over spring and areturn spring, as will become more apparent from a description of the operation of the snap switch. Further, the particular arrangement of the elements allows the C spring to provide adequate contact pressure between the contact 27 and the upper stop pontion 18b and lower stop portion 17b of the terminal members 18 andv17, respectively. Also, because of the contact pressure pro vided by the C spring and the arrangement of the elements, dead break between the contact 27 and the upper stop portion 1817 and lower stop portion 17b of terminal members 18 and `17 respectively, is inhibited. Again, due to the association of the elements, upon actuation and deactuation thereof, .the lever 25 exhibits a certain amount of longitudinal movement which results in contact wiping, thus insuring clean contact and terminal surfaces thereby reducing the possibility of welding therebetween.

In the condition shown in FIGURE l, the snap switch 10 is in a deactuated condition. Upon downward movement of the plunger 40, the lever 22 rotates clockwise about the pivotal connection A, thereby causing clock- Wise rotation of the pivotal connection B about the pivotal connection A and leftward longitudinal movement of the lever 25 with the contact wiping discussed above arising. At rest and during the initial actuating movement, the C spring 35 provides an upward force on the contact 27 resulting in contact pressure arising between the contact 27 and the upper stop portion 18b of the terminal member 18. Continued downward movement of the plunger 4i) finally results in the toggle point between the pivotal connections B, D, and E being attained. A=s this toggle point is passed, a snap action of the lever 25 and the contact 27 associated therewith results whereby the contact 27 is driven from engagement with the upper stopportion 18,1?l

of terminal member 18 into engagement with the lower stop portion 17b of the terminal member 17. In this condition, the arrangement assumes the position shown in FIGURE 3. The C spring 3-5 now provides a downward force 'so that the contact 27 engages the lower stop portion 17b of the terminal member 17 to provide an adequate contact force therebetween. The C spring 3S also provides an upward force on the left end portion of the lever 25 tending to return the arrangement to Vthe position shown in FIGURE l. Upon tlie removal of the input force from the plunger 40, the force provided by the C spring 35 on the left end portion of the lever 25 results in the pivotal connection B rotating counter clockwise about the pivotal connection A until the toggle point between the pivotal connections `B, D, and E is again attained. Upon this toggle point being passed, the lever 25 returns with a snap action to its original position as shown in FIGURE l. Again, during the upward movement of the pivotal connection B, leftward longitudinal movement of the lever 25 is encountered, so that wiping between the cont-act and the lower stop portion 17h of the terminal member 17 arises. It should be noted that the toggle point between the pivotal connections A, D, and E is never encountered so that the force provided by the C'spring'SS with the arrangement in the condition shown in FIGURE 3 is sufficient to retunn the arrangement to the condition shown in FIGURE l upon removal of the input force. Of course, Vif the toggle point between the pivotal connections A, D, and E was passed, the arrangement would not be self returning and either a reset mechanism ora return spring would be required.

While the drawing shows the snapswitch to be relatively large, it should be lappreciated that switches incorporating the teaching of the present invention have been successfully produced which'are 1/2 inch in length, 1/5 inch Vin width, and 1/2 inch in -overallheight Even withsuch very high .miniaturizatiom thexgstructure disclosed herein provides excellent load carrying capacity, as set forth in the Abeginning of the specification, good repeatability and low operating force. Further, switches of thissize exhibit the 'contact wiping, the absence of dead break and high Contact pressure attributes discussed above.

Due to the simplicity of the elements of the snap switch, assembly of -such highly miniaturized switches proves little problem. Further, due to the relative small cross section of the upper portion 16h of the terminal member 16 and the thinness of the upstanding leg 30a of the angle member 30, these can -be easily bent to calibrate the switch. Funther, the C spring 3S can be deformed to provide the necessary calibration.

Thus, an improved snap action mechanism has been disclosed which 'incorporates two tension elements anda compression element, simple in nature, which are so arranged 'as to allow the compression element to provide the force for snap over and return of the mechanism upon actuation and deactuation, respectively. Further, a ysnap action mechanism has been disclosed which provides good contact pressure, contact wiping and limits dead break and which is 'easily assembled and capablevof being calibrated by Vsimple expedients. Still further, the present invention is so devised as to be capable of being miniaturized to fa very high degree with none of the forernentioned attributes being adversely effected.

While a C spring has been disclosed in the singley embodiment, other types of compressive springs could be utilized. Similarly, where rigid tension members have been called for these could be merely tension springs. Other modifications could be made to the present invention, and therefore, the scope of the invention should be determined from the following claims.

-I claim:

l. A snap -switch arrangement comprising: a switch case including a base and a cover; a'first terminal memberv affixed Sto said base near a first extremity; a second terminal member and a third terminal member afiixed to said base so as to provide spaced stop portions near a second extremity of said base; a first rigid tension member extending toward said spaced stop portion and having a first end portion associated with said first terminal member so as to form a first pivotal connection; a second rigid tension member having a first end por-tion associated with the second end portion of said first tension member, the first end portion of said second tension member and the second end portion of said first tension member depending toward each other and interconnected to form a second pivotal connection having line contact therebetween; said second tension member having a second end portion including contact means for selectiveengagement with the stop portions of said second and third terminal members; a compression C spring partially disposed and movable in an opening provided in said second tension member and having a first end portion associated with a portion of a support member operatively fastened to said first terminal member so as to form a third pivotal connection and having a second end portion associated with an extremity of the opening in said second tension member so as to form a fourth pivotal connection, said third pivotal connection being located between said second and fourth pivotal connections; and a plunger slidably disposed in said cover for actuating said first tension member to cause snap movement of lsaid Contact means from one stop -portion to the other stop portion of said second and third terminal members upon the toggle point of said second, third `and fourth pivotal connections being attained; the elements being arranged so the toggle point of said first, third and fourth pivotal connections is never attained thereby effecting self-return of the arrangement upon deactuatiotn of the plunger.

2. A snap switch arrangement comprising: a base; a first terminal member afiixed to said base near a'first extremity; a second terminal member and a third terminal member afiixed to said base so as to provide spaced stop portions near a second extremity of said base; a first rigidtension member extending toward said spaced-stop portion and having a first end portion associated with said first terminal member so as to form a first pivotal connection; a second rigid tension member having a first end portion associated with the second end portion of said first tension member so as to form a second pivotal connection and having a second end portion including contact means for selective engagement with the stop portions of said second and third terminal members; and a compression spring having a first end portion associated with a portion of a support member operatively fastened to said base so as t'o form a third pivotal connection and having a second end portion vassociated with said second tension member near the second end portion so as to form a fourth pivotal connection, 'said third pivotal connection being located between said second and fourth pivotal connections; an input 'force applied to said first tension member arranged to cause snap movement of said contact means from one stop portion to the other stop portion of said second and third terminal members upon the toggle point of said second, third and fourth pivotal connections being attained; the elements being arranged so the toggle point `of said first, third and fourth pivotal connections is never attained thereby effecting self-return of the arrangement upon removal of the input force.

3. A snap switch arrangement comprising: a base; a first 'terminal member affixed to said base near a first extremity; a second terminal member and a third terminal member affixed to said base so as to provide spaced stop portions near a second extremity of said base; a first tension member extending toward said spaced stop portions and having a first end portion associated with said first terminal member so as to form a rst pivotal connection; a second tension member having a first end portion associated with the second end portion of said first tension member so -as to Vform a Ysecond pivotal connection and having a second end portion including contact means for selective engagement with the stop portions of said second and third terminal members; and compression spring means operatively connected to said second tension member and having an end portion associated with a portion of a support member operatively fastened to said base so as to form a third pivotal connection, said third pivotal connection being located between said second pivotal connection and said operative connection; an input force applied to said rst tension member between said rst and second pivotal connections arranged to cause snap movement of said contact means from one stop portion to the other stop portion of said second and third terminal members upon the toggle point of said second and third pivotal connections and said operative connection being attained;l

the elements arranged so the toggle point of said rst and third pivotal connections and said operative connection is never `attained thereby effecting self-return of the ar-Y rangement upon removal of the input force.

648,682 Great Britain Jan. 10, 1951. 

